Obscuring bus bars in electrochromic glass structures

ABSTRACT

Embodiments described include bus bars for electrochromic or other optical state changing devices. The bus bars are configured to color match and/or provide minimal optical contrast with their surrounding environment in the optical device. Such bus bars may be transparent bus bars.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. § 371to International Application PCT/US14/72362 (designating the UnitedStates), filed on Dec. 24, 2014 and titled “OBSCURING BUS BARS INELECTROCHROMIC GLASS STRUCTURES,” which claims benefit of and priorityto U.S. Provisional Patent Application No. 61/920,684, titled “OBSCURINGBUS BARS IN ELECTROCHROMIC GLASS STRUCTURES,” filed on Dec. 24, 2013,which are hereby incorporated by reference in their entireties and forall purposes.

FIELD

The embodiments disclosed herein relate generally to techniques forobscuring from view bus bars and other features within an electrochromic(EC) glass structure assembly having, for example, one or more insulatedglass units (IGUs).

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960s, electrochromicdevices, and particularly electrochromic windows, still unfortunatelysuffer various problems and have not begun to realize their fullcommercial potential despite many recent advances in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

BRIEF SUMMARY

Certain embodiments described herein generally relate to techniques forobscuring bus bars in electrochromic glass structures.

Certain embodiments pertain to an insulated glass unit (IGU) comprisingfirst and second substantially transparent substrates, a spacer betweenthe first and second substantially transparent substrates, a primaryseal, an electrochromic device, and a bus bar associated with theelectrochromic device. The primary seal is between the spacer and thefirst substantially transparent substrate and between the spacer and thesecond substantially transparent substrate. The electrochromic device ison at least one of the first and second substantially transparentsubstrates. The bus bar is associated with the electrochromic device andlocated in the primary seal, the bus bar camouflaged to blend in withits background. In some cases, camouflaged can mean having minimaloptical contrast between the bus bar and the primary seal and/or spacer.In one case, the bus bar is made of an electrically conductive materialcomprising a tinting agent configured to approximate the color andluminescence of the bus bar to its background.

Certain embodiments pertain to an electrochromic glass structurecomprising a substantially transparent substrate, an electrochromicdevice disposed on the substantially transparent substrate. Theelectrochromic device has one or more transparent conductive layers. Theelectrochromic glass structure further comprises a bus bar configured topower the electrochromic device and an opaque obscuring layer betweenthe one or more transparent conductive layers and the substantiallytransparent substrate in a region proximal the bus bar. In some cases,the opaque obscuring layer is located in a region between the bus barand the substantially transparent substrate. In some cases, the opaqueobscuring layer has at least a width configured to block view of the busbar from an observer outside the electrochromic glass structure. In somecases, the bus bar is made of a material with a color and luminescenceconfigured to blend in with background. In one case, the bus barmaterial comprises one or more of carbon black, graphite, graphite-basedmaterials, graphene, or graphene-based materials.

Certain embodiments pertain to an IGU comprising a first pane having afirst substantially transparent substrate, an electrochromic devicedisposed on the second substantially transparent substrate, theelectrochromic device comprising a first transparent conductive layerproximal the second substantially transparent substrate, anelectrochromic stack, and a second transparent conductive layer. The IGUfurther comprises a second pane having a second substantiallytransparent substrate, a spacer between the first and second panes, aprimary sealant adhering the spacer to the first and second panes, and apair of bus bars on the first transparent conductive layer, nearest thefirst pane, and one or more transparent bus bars on the secondtransparent conductive layer. The pair of bus bars is located betweenthe spacer and the first substantially transparent substrate such thatthe spacer blocks view of the pair of bus bars from an observer viewingthrough the second pane. In some cases, the pair of bus bars is made ofmaterials configured to match color and luminescence to the spacerand/or the primary sealant. In some cases, the one or more transparentbus bars are in the viewable region of the IGU. In one case, theadditional one or more transparent bus bars are patterned onto the firstsubstantially transparent substrate and then the first transparentconductor layer is fabricated thereon. In one case, the additional oneor more transparent bus bars are embedded in the first substantiallytransparent substrate in at least in the viewable region of the IGU.

Certain embodiments pertain to an IGU or laminate comprising anelectrochromic device on at least one transparent substrate, of at leasttwo transparent substrates of the IGU or laminate and at least onetransparent bus bar configured to electrically power the electrochromicdevice. In some cases, the transparent bus bar comprises a transparentconductive material embedded with conductive particles. In some cases,the conductive particles are nanoparticles. In some cases, the at leastone transparent bus bar is a thin layer of metal or metal alloy. In oneexample, the thin layer of metal or metal alloy is between about 1 nmand about 10 nm thick. In another example, the thin layer of metal ormetal alloy is less than about 5 nm thick.

These and other features are described in more detail below withreference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic drawing of a cross section of an insulated glassunit (IGU) of an electrochromic window assembly.

FIG. 1B is a schematic drawing of plan views of the IGU in an un-tintedstate (left hand side illustration) and a tinted state (right hand sideillustration) from the perspective of the observer shown by theillustrated eye in FIG. 1A.

FIGS. 2A and 2B depict an electrochromic IGU configuration, according toembodiments.

FIG. 3A is a schematic illustration of an electrochromic window assemblywith butt joints between the four IGUs butted together, according toembodiments.

FIG. 3B are side views of different butt joint configurations, accordingto embodiments.

FIG. 3C is a schematic illustration of a cross sectional view of aportion of an electrochromic window assembly including a butt jointbetween two IGUs butted together, according to embodiments.

FIG. 4 is a schematic drawing of a portion of an electrochromic panehaving an opaque obscuring layer, according to embodiments.

FIG. 5A is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar within the viewable region, accordingto an embodiment.

FIG. 5B is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar within the viewable region, accordingto an embodiment.

FIG. 5C is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar within a viewable region, according toan embodiment.

FIG. 5D is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar within a viewable region, according toan embodiment.

FIG. 6A is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar) within a viewable region, according toan embodiment.

FIG. 6B is a drawing of a cross-sectional view of an EC IGU comprisingan optically unobtrusive bus bar within a viewable region, according toan embodiment.

FIG. 7 is a drawing of a cross section of an edge region of an IGUcomprising a spacer residing under a spacer, according to an embodiment.

FIG. 8 is a drawing of a cross-sectional of a spacer which has a notchon the bottom to accommodate the full length of a bus bar, according toan embodiment.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the presented embodiments.The disclosed embodiments may be practiced without some or all of thesespecific details. In other instances, well-known process operations havenot been described in detail to not unnecessarily obscure the disclosedembodiments. While the disclosed embodiments will be described inconjunction with the specific embodiments, it will be understood that itis not intended to limit the disclosed embodiments.

An electrochromic (EC) glass structure can refer to a structureincluding one or more EC panes (also referred to herein as EC lites)such as, for example, an insulated glass unit (IGU) or an EC panelaminated to another pane, EC or not. An example of an EC glassstructure assembly is an EC window assembly having one or more IGUs.Each IGU is manufactured from two or more panes where at least one ofthe panes is an EC pane. Each of the EC pane and/or mate lite of an IGUmay be alone or laminated to another pane for strength. The EC panecomprises a substantially transparent substrate (e.g., glass substrate)and an EC device fabricated on the substrate. Methods of fabricating ECpanes, laminates and IGUs can be found in U.S. patent application Ser.No. 13/456,056 titled “ELECTROCHROMIC WINDOW FABRICATION METHODS,” filedon Apr. 25, 2012, which is hereby incorporated by reference in itsentirety. In these fabrication methods, EC panes with fully assembled ECdevices are fabricated first, and then IGUs are manufactured using oneor more of the EC panes. Typically, an IGU is formed by placing asealing separator, for example, a gasket or seal (for example made ofPVB (polyvinyl butyral), PIB or other suitable elastomer) around theperimeter of the substrate. In some embodiments, the sealing separatorincludes a metal, or other rigid material, spacer and sealant betweenthe spacer and each substrate. After the panes are sealed to the spacer,a secondary seal is provided around the outer perimeter of the spacer,for example a polymeric material, e.g. a silicone-based material thatresists water and that adds structural support to the assembly. In somecases, a desiccant may be included in the IGU frame or spacer duringassembly to absorb any moisture. In one case, the sealing separatorsurrounds the bus bars and electrical leads to the bus bars extendthrough the seal. Typically, but not necessarily, the IGU is filled withinert gas such as argon. The completed IGU can be installed in, forexample, a frame or wall and connected to a power source (or wirelesslypowered) and a controller to control power to transition the opticalstates of the EC device(s). Examples of bus bars and spacers can befound in U.S. patent application Ser. No. 13/312,057 titled “SPACERS FORINSULATED GLASS UNITS” and filed on Dec. 6, 2011, now U.S. Pat. No.8,711,465, and U.S. patent application Ser. No. 13/452,032 titled“ANGLED BUS BAR” and filed on Apr. 20, 2012, which are herebyincorporated by reference in their entirety.

In a conventional EC glass structure assembly, especially on larger sizesubstrates, manufacturers use a bus bar and/or scribe lines in theviewable area of the IGU, e.g. due to engineering or perceived need todo so. This has traditionally been aesthetically unpleasing due to thecontrast between the EC device and the scribe line and/or bus bar in theviewable area.

For example, referring to FIG. 1A, which shows a conventionalelectrochromic IGU, 100, and an observer viewing the IGU (as depictedwith the stylized eye) that might be able to see both bus bars and otherfeatures when the EC coating is darkened or in the clear state. FIG. 1Ais a schematic drawing of a cross section of an IGU 100 of an EC IGU100. In FIG. 1A, a spacer, 105, is used to separate a first EC pane 110from a second pane 220. The first EC pane includes an EC devicefabricated on a substantially transparent substrate such as a glasssubstrate. The second pane 220 in this example is a non-EC pane. Inother examples, second pane 220 can have an EC device thereon and/or oneor more coatings such as low-E coatings and the like. Between spacer 105and, in this example, the substrate of first EC pane 110 is a primaryseal, 130. This primary seal 130 is also between spacer 105 and thesecond non-EC pane 220. Around the perimeter of spacer 105 is asecondary seal, 140 (bus bar wiring may traverse the primary seal forconnection to controller). These seals aid in keeping moisture out ofthe interior space, 150, of IGU 100.

In FIG. 1A, areas 112(a) and 112 (b) represent where the EC device stackhas been removed (e.g., by laser scribing), in this example, at aperimeter region. In this example, the area 112(a) passes through thesecond transparent conducting oxide (TCO), the EC stack and the firstTCO, and may be able to isolate the operable EC device from otherportions of the EC device that were potentially damaged during edgedeletion. In certain cases, the EC stack comprises an EC layer, acounter electrode (CE) layer, and an optional discrete ion conducting(IC) layer. Area 112(b) also passes through the second TCO and thedevice stack, but not the bottom first TCO, as this serves as the lowerconductor in electrical communication with bus bar 2. Regardless, areas112(a) and 112 (b) allow light to pass through the glass, even thoughthe EC device layers may be darkened. In this example, the EC stack, thefirst TCO and the diffusion barrier were removed in the edge deletionareas, and the outer perimeter of the EC device does not pass under thespacer into the primary seal, thus areas 112(c) will also allow light topass through even when the EC device is darkened, because they have noEC coating.

In FIG. 1A, bus bar 1 160(a) is fabricated on the second TCO of the ECstack and bus bar 2 160(b) is fabricated on the first TCO. Theillustrated eye shows the perspective of an observer viewing the IGU 100from the outside. FIG. 1B shows plan views of IGU 100 in an un-tintedstate (left hand side illustration) and a tinted state (right hand sideillustration) from the perspective of the observer shown by theillustrated eye in FIG. 1A. As shown, unless the techniques forobscuring of certain embodiments are used, the bus bars and/or thescribe lines in IGU 100 are visible in contrast with its background ofthe EC device (tinted and untinted) and/or the surrounding spacer. Inthe tinted state, the scribe lines are visible against the first EC pane110 in the tinted state. Although not shown, the bus bar bus bar 1160(a) and bus bar 2 160(b) may also be partially visible in the tintedstate. In the untinted state, bus bar bus bar 1 160(a) and bus bar 2160(b) are visible. The issues related to visibility of bus bars andscribe lines in relation to conventional IGUs are addressed byembodiments described herein, but also, even with improved IGUs, whereno bus bars or scribe lines are in the viewable area, there may beissues related to the type of glazing into which IGUs are incorporated.

Improved IGUs, for example, as described in U.S. patent application Ser.No. 13/456,056, are configured with bus bars under the spacer, i.e. inthe primary seal, of the IGU (similarly, IGUs may have the bus bar inthe secondary seal area). This is illustrated in FIG. 2A. In FIG. 2A, apartial cross-section of an EC IGU 200, bus bar 270 is embedded in theprimary seal 230 of the IGU 200; that is, the bus bar is sandwichedbetween the glass substrate and the spacer 220. Though there should beinsulating primary sealant 230 between the bus bar and the spacer, inorder to avoid electrical shorting between the bus bar and spacer, anelectrically insulated spacer, e.g. polymeric (e.g. foam) or metalcoated with an insulating material (e.g. color matched to the sealant,e.g. gray or black insulating material), is used. In the illustratedexample, bus bar 270 is lying on the EC device 210 disposed on asubstrate. Thus when such IGUs are installed in a frame, there are nobus bars visible to the end user, because they are not in the viewablearea, see FIG. 2B; i.e. the frame blocks a line of sight to the busbars. Still, if such IGUs are glazed using a butt joint without flashingor other material covering the periphery of the IGU as a frame wouldotherwise do, an observer viewing the assembly from the outside will seebus bar 270 or other uncoated regions within the assembly through theglass as in the primary seal 230 or secondary seal 260, since the ECcoating is transparent. Since bus bars are typically fabricated from ametallic material such as silver ink, they usually have a metallic colorsuch as silver or copper. These metallic-colored bus bars can be visiblewhen seen in contrast with the rest of the assembly. It is undesirablefrom an aesthetic standpoint to be able to see these bus bars and otheruncoated regions (e.g., scribe lines) within the assembly.

For example, an observer viewing a butt joint between adjacent IGUs ofan EC window assembly might be able to view conventional metallic busbars within the assembly. FIG. 3A is a schematic drawing of an EC windowassembly 10(a) having butt joints between four (4) IGUs 100(a) buttedtogether. Butt joints are used in window structures to increase thevisible area by combining EC glass structures (e.g., IGUs) with littleor no extra framing added. Electrochromic window assemblies that have abutt joint generally have one or more structural member between the ECglass structures butted together that provide support at the joint. Inthe case of butted IGUs, for example, a structural member may providesupport between the panes of the butted IGUs, at least partially in thesecondary seal area of each IGU. In FIG. 3A, the EC window assembly10(a) includes butt joints without framing (or flashing) exterior to thepanes on either side. Although the illustrated embodiment shows adjacentIGUs butted together at a 180 angle, butt joints that provide a cornersuch as, for example, 45 degrees, 165 degrees, 90 degrees, etc. may alsobe used. In certain cases, mitering may also be used at a butt jointhaving a corner. FIG. 3B are side cross-sectional views of differentpossible butt joint configurations of embodiments. The illustrated buttjoints may be silicone butt joints in one example. In theseconfigurations, the bus bar is visible from the outside looking in(because the EC pane is typically mounted on the outer pane of an IGU),and this is an undesirable result.

FIG. 3C is a schematic drawing of a cross-sectional view of a portion ofan EC window assembly 10(b) including a butt joint 320 between two IGUs100(b) butted together. The butt joint 320 in FIG. 3C may be an exampleof a structure that is used to join the abutted IGUs 100(a) in FIG. 3A.In FIG. 3C, each IGU 100(b) includes two panes, each pane comprising asubstantially transparent substrate (e.g., glass or polymer substrate).For each IGU 100(b), one of the substrates includes an EC device 350 ona portion of the inner surface. In other embodiments, both substratesmay have EC devices 350 and/or the EC devices 350 may be on differentsurfaces of the substrates.

In FIG. 3C, the butt joint 320 includes a structural member 330 having agenerally rectangular cross-sectional shape. The structural member 330have opposing vertical and horizontal legs that provide structuralsupport by locating structural member 330 between the opposing panes, atlast partially in the secondary seal area of the adjoining IGUs.Depressions along the four corner edges of the structural member 330 areconfigured to interface with the panes of the IGUs. Although not shown,wires for electrical connectivity between the EC devices 350 and otherelements may run in the center volume of the structural member 330.

In FIG. 3C, there is at least some secondary sealant 380 (e.g., blacksilicone) between the structural member 330 and each spacer 340 andprimary seal 360. The IGUs 100(b) have an interior space 300, which maybe filled with an inert gas such as argon and pressurized. In thisexample, there is no framing or flashing used that extends outside ofthe exterior surfaces of the substrates, there is only secondary sealant380 between substrate edges. Bus bars 370 for powering the EC devices350 are located between the spacer 340 and the edge of the EC devices350. The illustrated eye shows the perspective of an observer viewingthe EC window assembly 10(b) from the outside. As illustrated, theobserver can view, through the glass, bus bar 370 under the spacer 340unless the techniques for obscuring bus bars of certain embodimentsdescribed herein are used. There is no frame, flashing or other materialto block the end user's line of site, the bus bars are obvious andvisually distracting. As depicted, the observer can view the bus bar oruncoated region through the proximal pane when viewing the IGU 100(b)from the outside.

Embodiments disclosed herein relate generally to techniques forobscuring from view bus bars and other features within an EC glassstructure assembly. Some examples of these techniques are describedbelow, in some cases with reference to the Figures. For example, certainembodiments are directed to camouflaging visible features to blend inwith their background. As another example, certain embodiments aredirected to adding an obscuring layer between the visible feature andthe observer to obscure it from view. In another example, certainembodiments are directed to transparent or substantially transparentfeatures.

A. Camouflaging Techniques

In certain embodiments, camouflaging techniques may be used to make thebus bar or other visible feature in the EC window assembly the same orsimilar color as the “background.” “Background” can refer to the elementor elements of the EC window assembly that are visible from the outsideof the assembly and are from the viewpoint of the observer behind thefeature being camouflaged. In many cases, the “background” to a bus baris the spacer or sealant in a primary seal of an IGU. In FIG. 3C, forexample, the background to the bus bars 370 is the sealant 360. Blackand gray are common background colors, although other colors may apply.The goal of camouflaging techniques is to reduce the contrast betweenthe bus bar or other visible feature and the background (e.g., sealantand/or spacer).

Contrast can refer to the difference in color (hue) and/or brightness(luminance) between the foreground feature being camouflaged and itsbackground. One metric of the differences in brightness is a luminancecontrast ratio between the measured luminance of the background andmeasured luminance of the feature being camouflaged. Examples ofdifferent luminance contrast ratios that can be used include Webercontrast (Cw=(L_(f)−L_(b))/L_(b)), Michelson contrast(C_(mich)=(L_(max)−L_(min))/(L_(max)+L_(min)), Luminance ratio(CR=L_(f)/L_(b)), and RMS contrast, where L_(f) is the measuredluminance of the feature and L_(b) is the measured luminance of thebackground. One metric of a difference in color contrast is the Delta E(or ΔE) developed by the International Commission on Illumination (CIE).Other measurements of color contrast may also be used such as CIE76,CIE94, CIEDE2000, etc.

In certain embodiments, a tinting agent can be added to the materialused to fabricate the bus bar to mask its normal color and brightnessand make it the same or similar to the background. Since black is acommon background color, carbon black, or graphite may be used as atinting agent in some cases. In certain cases, the tinting agent and/orthe amount of tinting agent is selected based on measured luminancecontrast ratio and measured color contrast (e.g., measured Delta E)between the final color of the bus bar and the background. In one case,the tinting agent and/or amount of tinting agent is selected to bewithin a range of acceptable contrast values.

In some embodiments, bus bars may be fabricated from non-conventionalbus bar materials that have the same color or similar color to thebackground and are also electrically conductive such as, for example,certain carbon-based materials. Some examples of suitable carbon-basedmaterials include materials having carbon black, graphite,graphite-based materials, graphene, graphene-based materials, etc. Thesematerials have been shown to have excellent electrical conductivity andmay be processed to fabricate conductive strips or similar structuressuitable for bus bars.

In other embodiments, the features in the background of the bus bar maybe fabricated to have the same or similar color as the bus bar (or othervisible feature being camouflaged). For example, tinting agents may beadded to the sealant or a coating applied over the sealant to make thesealant the same or similar color as the feature being camouflaging.

B. Intervening Obscuring Layer from View Techniques

In certain embodiments, techniques may be used to form an opaqueobscuring layer between the bus bar and an observer to block the view ofthe bus bar from the observer. In certain cases, the obscuring layer ismade of a material having a color that is the same or similar to thebackground. A tinting agent may be used in the opaque obscuring layer.The obscuring layer has at least a width needed to prevent an observerfrom viewing the bus bar being obscured from a range of viewing anglesor from all possible viewing angles (i.e. vantage points). For example,the obscuring layer has a width that is at least the width of the busbar. In these embodiments, there will be at least one TCO layer betweenthe bus bar and the obscuring layer.

In one embodiment, a tinted coating can be applied between the bus barand the EC coating's top TCO to mask its normal color and make it thesame or similar to the background color. The tinted coating may have atinting agent as discussed above. Similarly, the color of the tintedcoating may be selected so that the contrast between the tinted coatingand the background has a luminance contrast ratio and/or color contrastwithin a range of acceptable values. Preferably the tinted coating iselectrically conductive, e.g. if it covers the entire area that the busbar occupies on the EC coating.

In another embodiment, a tinted coating is applied between the ECcoating and the transparent substrate. FIG. 4 is a schematic drawing ofa portion of an EC pane 100(d) having an opaque obscuring layer 450,according to embodiments. The illustrated eye shows the perspective ofan observer viewing the EC pane 100(d) from the outside. In theillustrated example, the single pane includes a substantiallytransparent substrate 402 having one or more layers of an EC device 420.These layers include one or two TCO layers. The bus bar 410 is formed onthe one or more layers of the EC device 420. The opaque obscuring layeris formed between the one or more layers of the EC device 420 and thesubstantially transparent substrate 402 in a region adjacent the bus bar410. As illustrated, the observer is blocked from being able to view thebus bar 310 by the obscuring layer 450. Obscuring layer 450 is depictedas being approximately as thick as coating 420, but this is notnecessary. Layer 450 may be much thinner. For example, a typical ECdevice coating may be on the order of 1 micron thick; while theobscuring layer can be between about 1 nm and 500 nm thick; betweenabout 1 nm and about 100 nm thick; between about 1 nm and about 50 nmthick; or between about 1 nm and about 10 nm thick. The obscurationlayer may be sputter deposited, e.g. a metal oxide, metal, or othermaterial. The obscuration layer may be selectively applied, e.g. in thedesired areas, or e.g. applied across the entire glass surface andselectively removed from areas where it is not desired. In the latterexample, plasma or laser may be used to remove the obscuration layermaterial from the substrate.

Referring back to FIG. 3C, bus bar 370 can be blocked from view with anopaque obscuring layer located between the bus bar 370 and one or bothof the TCOs in the EC device 350 or between the EC device 350 and thesubstantially transparent substrate. The width of the obscuring layer isat least the width of the bus bar 370. In this example, the obscuringlayer may be made of material having the same or similar color tosealant 360 that is background to the bus bar 370.

Referring back to FIG. 1A, bus bar 1 160(a) can be blocked from viewwith an opaque obscuring layer located between the first TCO and thediffusion barrier or between the diffusion barrier and the substrateunder bus bar 2 160(b). Bus bar 2 160(b) can be blocked from view withan opaque obscuring layer located outside the second TCO under bus bar 1160(a).

C. Transparent or Otherwise Optically Unobtrusive Bus Bars and OtherTransparent Features

In certain embodiments, obscuring techniques include fabricating andusing a transparent, substantially transparent bus bar, or otherwiseoptically unobtrusive bar. In these cases, the bus bar will not bevisibly discernible and/or visually distracting to an observer. Anobserver viewing the general area of the bus bar will see through thebus bar and to any background (primary sealant and/or spacer) behind thebus bar or in the case of a transparent bus bar in the viewable area,will see through bus bar in the viewable area.

For example, if the bus bar 370 shown in FIG. 3C were fabricated to betransparent or substantially transparent, the observer from the vantagepoint of the illustrated eye outside the EC glass structure would viewthe sealant 360 when the EC device 350 is in the untinted state (ortinted but still allowing some light to pass through). As anotherexample, if bus bar 1 160(a) shown in FIG. 1A is fabricated to betransparent or substantially transparent according to an embodiment, theobserver from the vantage point of the illustrated eye would viewthrough the bus bar in the visible area of the IGU, thus avoiding avisually distracting, high contrast bus bar.

According to certain embodiments, a transparent or substantiallytransparent bus bar may be fabricated from a transparent orsubstantially transparent material having electrically conductiveproperties. For example, the transparent or substantially transparentbus bar may be made from an ITO or other TCO doped with anelectronically conductive agent such as conductive nanowires or otherconductive nanostructure. Although the dopant may introduce haze, thebus bar will be far less visible than a conventional bus bar. In certaincases, any haze that may be introduced will not be a problem since thebus bar will be viewed in contrast to its background (e.g., sealant). Inthese cases, the contrast between the bus bar and the background will beminimal and may not be discernable by an observer from outside the ECglass structure. In certain cases, the transparent bus bar may befabricated by screen printing a transparent or translucent inkcontaining metal nanoparticles, or by using masks during sputtering toproduce a thicker region of the TCO that serves as the transparent busbar. Also, low-haze metal doped transparent conductor materials aredescribed in the current literature. These low-haze materials can beused for transparent bus bars.

Optically Unobtrusive Bus Bars within Viewable Region

In certain embodiments, one or more transparent or substantiallytransparent or otherwise optically unobtrusive bus bars may be appliedto an EC lite within the viewable region of the EC window. The viewableregion can refer to the area of the EC window where an observer cangenerally see through the window unless the EC device(s) is tinted.Generally, the viewable region is defined by the region of the EC windowhaving a perimeter defined by the inner perimeter of the IGU spacerand/or the inner perimeter of a frame. One advantage of using bus barsin the viewable region is to improve switching uniformity and increasespeed of transition between optical states. These advantages may be moresignificant as EC lites and their associated windows are scaled up insize as techniques for manufacturing EC coatings become moresophisticated.

In some cases, the transparent or substantially transparent or otherwiseoptically unobtrusive bus bars may be made of material selected suchthat the refractive index of the entire EC device stack and theoptically unobtrusive bus bar less visibly distracting. In these cases,the material of the bus bar may be selected for a refractive index totune the material properties of the bus bar and EC stack to make the busbar less distinctive visually. For example, the material of the bus barand/or other material layers of the EC stack may be selected to avoid aninterference pattern. For example, the transparent bus bar may have arefractive index that approximates the TCO upon which it rests or theglass substrate, e.g. the transparent bus bar has a refractive index ofbetween about 1.3 and about 2.0.

In some cases, the transparent or substantially transparent or otherwiseoptically unobtrusive bus bars may be made of a conductive and/orsubstantially transparent material. In some cases, these bus bars may bemade of a thin layer of metal or metal alloy. In one example, the busbar may be a thickness in the range of 1 nm and 10 nm. In one example,the bus bar has a thickness of less than about 3 nm. In another example,the bus bar has a thickness of less than about 5 nm. In otherembodiments, the optically unobstrusive bus bars may be made of anon-metallic and conductive material. In certain cases, the opticallyunobstrusive bus bars may be made of silver nanowires or conductivecarbon nanotubes (CNT) in a binding paste (i.e. CNT or silver nanowirebased pastes).

In certain embodiments, the optically unobtrusive bus bars may befabricated onto the surface (e.g., bus bar 860(c) shown in FIG. 5D) of asubstrate or embedded into the substrate (e.g., bus bar 910(c) shown inFIG. 6A and bus bar 930(c) shown in FIG. 6B) in some cases. For example,the optically unobstrusive bus bars may be fabricated onto thesubstantially transparent substrate by patterning material such as, forexample, by rolling lithography. In another example, the opticallyunobstrusive bus bars may be embedded into the substrate by firstgrinding or otherwise fabricating trenches into the substrate, fillingthe trenches with the bus bar material, and then planarizing thesubstrate before depositing the EC device layers. In this example,distortion of the EC device layers may be avoided.

FIG. 5A is a drawing of a cross-sectional view of an EC IGU, 500,comprising an optically unobtrusive bus bar 560(c) within a viewableregion, according to an embodiment. FIG. 5A also includes an observerviewing the IGU (as depicted with the stylized eye) from, for example,the inside of a building. This is a not-to-scale, partially explodedview showing certain components of the fabricated assembly of the IGU500 separated. In FIG. 5A, a spacer, 570, is used to separate an EC pane(lite), 510, from a non-EC pane 520. The first EC pane 510 comprises afirst TCO, an EC stack, and second TCO, fabricated on a firstsubstantially transparent substrate, such as a glass substrate. Thesecond pane 520 is a non-EC pane that is a substantially transparentsubstrate. In other examples, the second pane 520 can have an EC devicethereon and/or one or more coatings such as low-E coatings and the like.Although not shown, between spacer 570 and, in this example, the firstsubstrate of first EC pane is a primary seal. This primary seal is alsobetween spacer 570 and the second non-EC pane 520. Around the outerperimeter of spacer 570, and between the substrates, is fabricated asecondary seal (not shown). These seals aid in keeping moisture out ofthe interior space, 590, of the IGU 500.

In FIG. 5A, the EC IGU 500 comprises a transparent or substantiallytransparent or otherwise optically unobtrusive bus bar 560(c) fabricatedon the second TCO of the first EC pane 510 in the viewable area of theIGU 500 between the spacers 570. The EC IGU 500 further comprises twobus bars 560(a) fabricated on the first TCO of the first EC pane 510 andtwo bus bars 560(b) (which are optional) fabricated on the second TCOoutside the generally viewable area of the IGU 500. Bus bars 560(a) and560(b) are blocked by the spacer 570 from view by an observer from theviewpoint of the stylized eye. In this example, the bus bars 560(a)and/or 560(b) are made of or coated by a material that blends inoptically with the background of the spacer 570 so that an observer fromthe opposite side (e.g., outside the building) cannot discern the busbars 560(a) and 560(b). In other cases, the bus bars 560(a) and/or560(b) may be transparent or substantially transparent or otherwiseoptically unobtrusive. That is, bus bars 560(a) would be discernablefrom the viewpoint of an observer from the opposite side unless bus bars560(a) blend into the background of the spacer 570 or are opticallyunobtrusive. Also, bus bars 560(b) would be discernable from theopposite side if the EC device is in the un-tinted state and may bediscernable if the EC device is in the tinted state unless bus bars560(a) blend into the background of the spacer 570 or are opticallyunobtrusive. Although a single optically unobtrusive bus bar 560(c) isshown in the illustrated example, additional bus bars 560(c) may befabricated on the first TCO, the EC stack, the second TCO, and/oronto/into the substrate in other examples. One embodiment, for example,is an EC device coating with multiple bus bars on the second TCO(upper), e.g. EC device 510 b. The bus bars may be substantiallytransparent, e.g. made of metal, or other transparent materialsdescribed herein. In one embodiment, the EC device has, e.g. two busbars on the bottom TCO, e.g. configured as depicted in FIG. 5A, that is,under the spacer. In other embodiments the bottom TCO has a bus bar oneach side of the bottom TCO, e.g. four bus bars or two L-shaped busbars. In one embodiment, the top TCO has two L-shaped bus bars,substantially transparent, while the bottom TCO has bus bars configuredas described in the previous two sentences.

FIG. 5B is a drawing of a cross-sectional top view of an EC IGU, 600,comprising an optically unobtrusive bus bar 660(c) within a viewableregion, according to an embodiment. FIG. 5B also includes an observerviewing the IGU from, for example, the inside of a building. This is anot-to-scale, partially exploded view showing certain components of thefabricated assembly of the IGU separated. In FIG. 5B, a spacer, 670, isused to separate an EC pane (lite), 610, from a non-EC pane 620. Thefirst EC pane 610 comprises a first TCO, an EC stack, and second TCO,fabricated on a first substantially transparent substrate, such as aglass substrate. The second pane 620 is a non-EC pane that is asubstantially transparent substrate. In other examples, the second pane620 can have an EC device thereon and/or one or more coatings such aslow-E coatings and the like. Although not shown, between spacer 670 and,in this example, the first substrate of first EC pane is a primary seal.This primary seal is also between spacer 670 and the second non-EC pane620. Around the perimeter of spacer 670 is a secondary seal. These sealsaid in keeping moisture out of the interior space, 690, of the IGU 600.

In FIG. 5B, the EC IGU 600 comprises a transparent or substantiallytransparent or otherwise optically unobtrusive bus bar 660(c) fabricatedon the EC stack of the first EC pane 610 in the viewable area of the IGU600 between the spacers 670. The EC IGU 600 further comprises two busbars 660(a) fabricated on the first TCO of the first EC pane 610 and twobus bars 660(b) (which are optional) fabricated on the second TCOoutside the generally viewable area of the IGU 500. In other cases, thetwo bus bars 660(b) may be fabricated on the EC stack of the first ECpane 610. In the illustrated example, bus bars 660(a) and 660(b) areblocked by the spacer 670 from view by an observer from the viewpoint ofthe stylized eye. In this example, the bus bars 660(a) and/or 660(b) aremade of or coated by a material that blends in optically with thebackground of the spacer 670 so that an observer from the opposite side(e.g., outside the building) cannot discern the bus bars 660(a) and660(b). In other cases, the bus bars 660(a) and/or 660(b) may betransparent or substantially transparent or otherwise opticallyunobtrusive. That is, bus bars 660(a) would be discernable from theviewpoint of an observer from the opposite side unless bus bars 660(a)blend into the background of the spacer 670 or are opticallyunobtrusive. Also, bus bars 660(b) would be discernable from theopposite side if the EC device is in the un-tinted state and may bediscernable if the EC device is in the tinted state unless bus bars660(a) blend into the background of the spacer 670 or are opticallyunobtrusive. Although a single optically unobtrusive bus bar 660(c) isshown in the illustrated example, additional optically unobtrusive busbars 660(c) may be fabricated on the first TCO, the EC stack, the secondTCO, and/or onto/into the substrate in other examples.

FIG. 5C is a drawing of a cross-sectional top view of an EC IGU, 700,comprising an optically unobtrusive bus bar 760(c) within a viewableregion, according to an embodiment. FIG. 5C also includes an observerviewing the IGU from, for example, the inside of a building. This is anot-to-scale, partially exploded view showing certain components of thefabricated assembly of the IGU separated. In FIG. 5C, a spacer, 770, isused to separate an EC pane (lite), 710, from a non-EC pane 720. Thefirst EC pane 710 comprises a first TCO, an EC stack, and second TCO,fabricated on a first substantially transparent substrate, such as aglass substrate. The second pane 720 is a non-EC pane that is asubstantially transparent substrate. In other examples, the second pane720 can have an EC device thereon and/or one or more coatings such aslow-E coatings and the like. Although not shown, between spacer 770 and,in this example, the first substrate of first EC pane is a primary seal.This primary seal is also between spacer 770 and the second non-EC pane720. Around the perimeter of spacer 770 is a secondary seal. These sealsaid in keeping moisture out of the interior space, 790, of the IGU 700.

In FIG. 5C, the EC IGU 700 comprises a transparent or substantiallytransparent or otherwise optically unobtrusive bus bar 760(c) fabricatedon the first TCO of the first EC pane 710 in the viewable area of theIGU 700 between the spacers 770. The EC IGU 700 further comprises twobus bars 760(a) fabricated on the first TCO of the first EC pane 710 andtwo bus bars 760(b) fabricated on the second TCO outside the generallyviewable area of the IGU 700. In the illustrated example, bus bars760(a) and 760(b) are blocked by the spacer 770 from view by an observerfrom the viewpoint of the stylized eye. In this example, the bus bars760(a) and/or 760(b) are made of or coated by a material that blends inoptically with the background of the spacer 770 so that an observer fromthe opposite side (e.g., outside the building) cannot discern the busbars 760(a) and 760(b). In other cases, the bus bars 760(a) and/or760(b) may be transparent or substantially transparent or otherwiseoptically unobtrusive. That is, bus bars 760(a) would be discernablefrom the viewpoint of an observer from the opposite side unless bus bars760(a) blend into the background of the spacer 770 or are opticallyunobtrusive. Also, bus bars 760(b) would be discernable from theopposite side if the EC device is in the un-tinted state and may bediscernable if the EC device is in the tinted state unless bus bars760(a) blend into the background of the spacer 770 or are opticallyunobtrusive. Although a single optically unobtrusive bus bar 760(c) isshown in the illustrated example, additional bus bars 760(c) may befabricated on the first TCO, the EC stack, the second TCO, and/oronto/into the substrate in other examples.

FIG. 5D is a drawing of a cross-sectional top view of an EC IGU, 800,comprising an optically unobtrusive bus bar 860(c) within a viewableregion, according to an embodiment. FIG. 5D also includes an observerviewing the IGU from, for example, the inside of a building. This is anot-to-scale, partially exploded view showing certain components of thefabricated assembly of the IGU separated. In FIG. 5D, a spacer, 870, isused to separate an EC pane (lite), 810, from a non-EC pane 820. Thefirst EC pane 810 comprises a first TCO, an EC stack, and second TCO,fabricated on a first substantially transparent substrate, such as aglass substrate. The second pane 820 is a non-EC pane that is asubstantially transparent substrate. In other examples, the second pane820 can have an EC device thereon and/or one or more coatings such aslow-E coatings and the like. Although not shown, between spacer 870 and,in this example, the first substrate of first EC pane is a primary seal.This primary seal is also between spacer 870 and the second non-EC pane820. Around the perimeter of spacer 870 is a secondary seal. These sealsaid in keeping moisture out of the interior space, 890, of the IGU 800.

In FIG. 5D, the EC IGU 800 comprises a transparent or substantiallytransparent or otherwise optically unobtrusive bus bar 860(c) fabricatedon the surface of the substrate of the first EC pane 810 in the viewablearea of the IGU 800 between the spacers 870. For example, thetransparent or otherwise optically unobtrusive bus bar 860(c) may bepatterned on the substrate with, for example, rolling lithography. TheEC IGU 800 further comprises two bus bars 860(a) fabricated on the firstTCO of the first EC pane 810 and two bus bars 860(b) fabricated on thesecond TCO outside the generally viewable area of the IGU 800. In othercases, the two bus bars 860(b) may be fabricated on the substrate of thefirst EC pane 810. In the illustrated example, bus bars 860(a) and860(b) are blocked by the spacer 870 from view by an observer from theviewpoint of the stylized eye. In this example, the bus bars 860(a)and/or 860(b) are made of or coated by a material that blends inoptically with the background of the spacer 870 so that an observer fromthe opposite side (e.g., outside the building) cannot discern the busbars 860(a) and 860(b). In other cases, the bus bars 860(a) and/or860(b) may be optically unobtrusive. That is, bus bars 860(a) would bediscernable from the viewpoint of an observer from the opposite sideunless bus bars 860(a) blend into the background of the spacer 870 orare optically unobtrusive. Also, bus bars 860(b) would be discernablefrom the opposite side if the EC device is in the un-tinted state andmay be discernable if the EC device is in the tinted state unless busbars 860(a) blend into the background of the spacer 870 or are opticallyunobtrusive. Although a single optically unobtrusive bus bar 860(c) isshown in the illustrated example, additional bus bars 860(c) may befabricated on the first TCO, the EC stack, the second TCO, and/oronto/into the substrate in other examples.

In some cases such as the illustrated examples shown in FIGS. 6A and 6B,one or more transparent or substantially transparent or otherwiseoptically unobtrusive bus bars may be embedded in the substrate of an ECpane in the viewable area of an EC window. For example, the opticallyunobtrusive bus bars may be embedded into the substrate by firstgrinding or otherwise fabricating trenches into the substrate, fillingthe trenches with the bus bar material, and then planarizing thesubstrate before depositing the EC device layers. FIG. 6A illustrates anexample with a single optically unobtrusive bus bar embedded in thesubstrate of an EC pane. FIG. 6B illustrates an example with multipleoptically unobtrusive bus bars embedded in the substrate of an EC pane.

FIG. 6A is a drawing of a cross-sectional top view of an EC IGU, 900,comprising an optically unobtrusive bus bar 910(c) within a viewableregion, according to an embodiment. FIG. 6A also includes an observerviewing the IGU from, for example, the inside of a building. This is anot-to-scale, partially exploded view showing certain components of thefabricated assembly of the IGU separated. In FIG. 6A, a spacer, 925, isused to separate an EC pane (lite), 902, from a non-EC pane 904. Thefirst EC pane 902 comprises a first TCO, an EC stack, and second TCO,fabricated on a first substantially transparent substrate, such as aglass substrate. The second pane 904 is a non-EC pane that is asubstantially transparent substrate. In other examples, the second pane904 can have an EC device thereon and/or one or more coatings such aslow-E coatings and the like. Although not shown, a primary seal may liebetween the spacer 925 and the substrate of the first EC pane 902 andalso between the spacer 925 and the second non-EC pane 904. Although notshown, a second seal lies around the perimeter of the spacer 925. Theseseals aid in keeping moisture out of the interior space, 927, of the IGU900.

In FIG. 6A, the EC IGU 900 comprises a transparent or substantiallytransparent or otherwise optically unobtrusive bus bar 910(c) embeddedin the substrate of the first EC pane 902 in the viewable area of theIGU 900 between the spacers 925. In this example, distortion of the ECdevice layers may be avoided. The EC IGU 900 further comprises two busbars 910(a) fabricated on the first TCO of the first EC pane 902 and twobus bars 910(b) fabricated on the second TCO outside the generallyviewable area of the IGU 800. In other cases, the two bus bars 910(b)may also be embedded in the substrate of the first EC pane 902. In theillustrated example, bus bars 910(a) and 910(b) are blocked by thespacer 925 from view by an observer from the viewpoint of the stylizedeye. In the illustrated example, the bus bars 910(a) and/or 910(b) aremade of or coated by a material that blends in optically with thebackground of the spacer 870 so that an observer from the opposite side(e.g., outside the building) cannot discern the bus bars 910(a) and910(b). In other cases, the bus bars 910(a) and/or 910(b) may beoptically unobtrusive. That is, bus bars 910(a) would be discernablefrom the viewpoint of an observer from the opposite side unless bus bars910(a) blend into the background of the spacer 870 or are opticallyunobtrusive. Also, bus bars 910(b) would be discernable from theopposite side if the EC device is in the un-tinted state and may bediscernable if the EC device is in the tinted state unless bus bars910(a) blend into the background of the spacer 870 or are opticallyunobtrusive.

FIG. 6B is a drawing of a cross-sectional top view of an EC IGU, 950,comprising an optically unobtrusive bus bar 980(c) within a viewableregion, according to an embodiment. FIG. 6B also includes an observerviewing the IGU 950 from, for example, the inside of a building. This isa not-to-scale, partially exploded view showing certain components ofthe fabricated assembly of the IGU separated. In FIG. 6B, a spacer, 970,is used to separate an EC pane (lite), 960, from a non-EC pane 962. Thefirst EC pane 960 comprises a first TCO, an EC stack, and second TCO,fabricated on a first substantially transparent substrate, such as aglass substrate. The second pane 962 is a non-EC pane that is asubstantially transparent substrate. In other examples, the second pane962 can have an EC device thereon and/or one or more coatings such aslow-E coatings and the like. Although not shown, a primary seal may liebetween the spacer 970 and the substrate of the first EC pane 960 andalso between the spacer 970 and the second non-EC pane 962. Although notshown, a second seal lies around the perimeter of the spacer 970. Theseseals aid in keeping moisture out of the interior space, 990, of the IGU950.

In FIG. 6B, the EC IGU 950 comprises five (5) optically unobtrusive busbar 980(c) embedded in the substrate of the first EC pane 902 in theviewable area of the IGU 950 between the spacers 970. Although five (5)optically unobtrusive bus bars 980(c) are shown in the illustratedexample, other numbers may be used. The EC IGU 950 further comprises twobus bars 980(a) fabricated on the first TCO of the first EC pane 960 andtwo bus bars 980(b) fabricated on the second TCO outside the generallyviewable area of the IGU 950. In other cases, the two bus bars 980(b)may also be embedded in the substrate of the first EC pane 960. In theillustrated example, bus bars 980(a) and 980(b) are blocked by thespacer 970 from view by an observer from the viewpoint of the stylizedeye. In the illustrated example, the bus bars 980(a) and/or 980(b) aremade of or coated by a material that blends in optically with thebackground of the spacer 970 so that an observer from the opposite side(e.g., outside the building) cannot discern the bus bars 980(a) and980(b). In other cases, the bus bars 980(a) and/or 980(b) may betransparent or substantially transparent or otherwise opticallyunobtrusive. That is, bus bars 980(a) would be discernable from theviewpoint of an observer from the opposite side unless bus bars 980(a)blend into the background of the spacer 970 or are opticallyunobtrusive. Also, bus bars 980(b) would be discernable from theopposite side if the EC device is in the un-tinted state and may bediscernable if the EC device is in the tinted state unless bus bars980(a) blend into the background of the spacer 970 or are opticallyunobtrusive.

In one embodiment, an EC device has multiple transparent bus barsembedded in the substrate and also multiple transparent bus bars on thetop TCO, as depicted in FIG. 5A (bottom). This configuration allows moreeven and faster tinting of the EC device stack. The bus bars on the topand bottom of the device structure may be parallel or not. Advantages tohaving non-parallel bus bars, e.g., is wiring of the bus bar ends foreach TCO can be done on orthogonal sides. The number of transparent busbars on the top and or bottom of the EC device as described herein canbe one, two, three, four, five or more; depending on the size of thesubstrate the conductivity of the bus bar material used, theconductivity of the TCO to which the bus bars are electricallycommunicating with, switching speed desired, etc.

D. Matching Resistive Properties of Conductor Layers Using Bus Bars.

Typically conductor layers in an EC device are designed to matchresistively to each other. In some cases, these conductor layers may notmatch, for example, the top and bottom TCOs may have substantiallydifferent electrical conductivity. For example the bottom TCO may have alow resistivity, e.g. <5 ohms/sq, while the top TCO might have aresistivity of greater than 10 ohms/sq. In these cases, the material ofthe bus bar may be selected to compensate for the resistive propertiesand to match the resistive properties of the conductive layers. Forexample, as depicted in the bottom portion of FIG. 5A, a series oftransparent bus bars may be fabricated on the top TCO to compensate forthis resistivity difference, i.e. allow more voltage to be appliedacross the top TCO and therefore compensate for its lower resistivitythan the bottom TCO. In fact, this is one desirable construct; i.e.where a top TCO is purposefully fabricated with a higher resistivitythan the bottom TCO, in anticipation of further fabricating multipletransparent bus bars thereon (so as not to have a final device structurethat would otherwise have a resistivity mismatch where the top TCO has anet lower resistivity than the bottom TCO due to added conducting busbars on the top TCO).

F. Bus Bars Residing Under Spacer

Some conventional IGUs have a bus bar on the inner surface of an EC litethat traverses the primary seal (between the spacer and the EC pane).That is, this bus bar is located on this inner surface running primarilywithin the inner perimeter of the spacer and exits through the primaryseal under the spacer to connect to a power line outside the outerperimeter of the spacer. In these IGUs, the EC coating does not lieoutside the inner perimeter of the spacer i.e. under the spacer.Typically, these conventional IGUs also have scribe lines in the ECcoating within this inner perimeter of the spacer.

Traversing the primary seal with the bus bar can create a possible leakpath through the seal along a weak seal between the bus bar and theprimary seal. Some conventional systems use a coating applied over thebus bar to keep the IGU sealed from leaking gas from the sealed spacewithin the IGU. These conventional IGUs use blocking material to preventviewers from seeing the bus bars from both sides of the IGU from withinthe inner perimeter of the spacer. These IGUs use a laminated outer liteto sandwich the blocking material between a support substrate and aninner substrate having the EC device on the opposite surface from theblocking material. This block material in the laminated lite must alsoblock the scribe lines from viewers as well. From one side of the IGU, ablocking layer is used to prevent view of the bus bars and scribe lines.From the other side, material is applied over the bus bar to blend inwith the background material in the laminated lite. This blockingmaterial takes up valuable area within the inner perimeter of the spacerthat would otherwise be viewable area. Embodiments described hereindiffer in that they do not occupy viewable area by design (if they do itis de minimus).

In certain aspects, bus bars of EC glass structures described hereinreside almost entirely under the spacer. In these cases, the bus bardoes not pass through the inner diameter and avoids creating a leak pathin the seal that could potentially allow gas within the sealed volume ofthe IGU to leak out. Since these bus bars reside under the spacer (e.g.,embedded in the seal or the EC coating), the spacer itself blocks thebus bars from being viewed from one side. In this case, only a singledirection of view of the bus bars from the other side must be obscured.In this direction, the bus bars have the primary seal of the spacer inthe background. Since only the view outside of the inner perimeter ofthe spacer needs to be blocked from view, much of the area within theinner perimeter of the spacer is available as viewable area.

In certain aspects, an obscuration layer is located at the sameinterface as the EC coating, where the interface is between an inner IGUsubstrate and the spacer. The obscuration layer is only required toblock the view of the bus bar from the single direction since it liesunder the spacer and cannot be seen through the opposite side throughthe spacer.

In certain aspects, the obscuration layer does not reside within theinner perimeter of the spacer. The obscuration layer is only blockingfrom view the embedded bus bar with the spacer in the background. Asdiscussed above, the bus bar does not reside within the inner perimeterof the spacer and thus, there would be no reason to place an obscurationlayer within the inner perimeter. Furthermore, the obscuration layer theobscuration layer need only be the width of the bus bar or about thewidth of the bus bar to block the view of the bus bar. For example, inkor other materials may be applied to an area that does not exceed thespacer's inner perimeter.

Examples of bus bars residing under spacers can be found in U.S. patentapplication Ser. No. 14/152,873 titled “SPACERS FRO INSULATED GLASSUNITS,” and filed on Jul. 10, 2014, which is hereby incorporated byreference in its entirety. FIG. 7 shows an example of a cross section,1100, of an edge region of an IGU where the spacer 1110 of the IGU and abus bar 1120 reside. In the illustration, the bus bar 1120 resides underthe spacer 1110. As illustrated, a spacer, 1110, is sandwiched betweentwo sheets of glass near the edge of the IGU. In a typical design, theglass interfaces directly with a primary seal material, 1115, (e.g., athin elastomeric layer, such as PIB or PVB), which is in direct contactwith spacer 1110. In some embodiments, spacer 1110 may be metal spacer,such as a steel spacer or a stainless steel spacer, for example. Thisthree-part interface (i.e., glass/primary seal material/spacer) existson both a top piece of glass and a bottom piece of glass. Spacer 1110may have a hollow structure, as depicted in FIG. 7. In some embodiments,the spacer may have a substantially rectangular cross section. At aminimum, spacers described herein have at least two surfaces, eachsubstantially parallel to the lites of the IGU in which they are to beincorporated. The remaining cross section, e.g., surfaces of the spacerthat face the interior space of the IGU and the exterior, secondary sealarea, space may have any number of contours, i.e., they need not beflat, but may be. In some embodiments, the top and bottom outer cornersof the spacer are beveled and/or rounded to produce a shallower angle inthese areas. Rounding, beveling, or smoothing may be included to ensurethere are no sharp edges that might enhance electrical shorting. Anelectrochromic device stack, 1105, is fabricated on the lower glasslite, as depicted. A bus bar, 1120, is located on electrochromic devicestack 1105 in order to make electrical contact with one of theelectrodes of the device. In this example, bus bar 1120 is betweenspacer 1110 and the lower glass lite. This is accomplished byconfiguring one of the aforementioned surfaces below (see top surface ofspacer 1110) or above (see bottom surface of spacer 1110) the othersurface on the face of the spacer that forms the primary seal with theglass surface. This configuration of surfaces forms “notch” 1101; seefurther description below. Primary seal material 1115 serves as aninsulating layer between bus bar 1120 and spacer 1110. Spacerembodiments with notches may help to accommodate added verticalthickness, e.g. due to obscuration layers.

There are two primary distinctions between a typical spacer design andspacer 1110 shown in FIG. 7. First, spacer 1110 is relatively thicker(wider) in the direction parallel to the glass sheet (i.e., a largerfootprint). A conventional metal spacer is approximately 6 millimetersin width. Spacer 1110 is about two times to about two and one half times(about 2× to about 2.5×) that width. For example, spacer 1110 may beabout 10 millimeters to about 15 millimeters wide, about 13 millimetersto about 17 millimeters wide, or about 11 millimeters wide. Thisadditional width may provide a greater margin of error in a sealingoperation compared to a conventional spacer.

The second significant distinction of spacer 1110 from a conventionalspacer is in the use of recesses or notches 1101 on the upper and lowerinner corners of spacer 1110. In some embodiments, a spacer may includetwo notches, and in some embodiments, the spacer may include one notch.Two notches, e.g., as depicted in FIG. 7, may be used for an IGUcontaining two electrochromic lites, or may be useful in fabricatingIGUs with only one electrochromic light. When using a spacer with twonotches in an IGU containing one electrochromic lite, there is no needfor special placement of a single notch toward the electrochromic lite.In some embodiments, a recess or notch may extend from a corner of oneside of the rectangular cross section of the spacer to a point along theone side of the rectangular cross section of the spacer. At least onenotch provides an area for covering the bus bar formed on the glasssurface and/or covering the bus bar formed on electrochromic devicestack 505 formed on the glass surface. In some embodiments, the bus baris about 2 millimeters to about 3 millimeters in width and about 0.01millimeters to about 0.1 millimeter in height (thickness). The bus barlength depends on the window size. In some embodiments, a bus bar mayhave a length about the length of the electrochromic device. The addedwidth, along with the “notched” profile of spacer 1110 that accommodatesthe bus bar, creates a region of “encapsulation” whereby the bus bar isunlikely to contact the spacer at any point along the length of the busbar, but is encapsulated in the primary sealant.

In some embodiments, the portion of the spacer's face that does notinclude the notch (i.e., the outer portion of the spacer) isapproximately the same width as a normal spacer employed innon-electrochromic IGU applications. As depicted in FIG. 7, bus bar 1120is entirely covered by the spacer 1110. As a consequence, the bus bar isnot visible to a user of the window.

In FIG. 7, electrochromic device stack 1105 extends underneath bus bar1120 and partially into the region formed by notch 1101 in spacer 1110.As noted above, an electrochromic device stack typically includes aconductive electrode layer such as ITO or TEC. Electrochromic devicestack 1105 may be entirely removed from the edge of the glass surface byan edge deletion process, described above. However, the removal by edgedeletion may not extend entirely up to the edge of the bus bar, as thiswould be unacceptable given normal process tolerances. Therefore,electrochromic device stack 1105 may extend just slightly beyond bus bar1120, e.g., while still residing in notch 1101.

FIG. 8 shows an example of a cross-sectional illustration of a spacerwhich has a notch on the bottom to accommodate the full length of anembedded bus bar. As shown in FIG. 8, a spacer, 1205, is between twoglass lites, 1210 and 1215. In some embodiments, spacer 1205 may be ametal spacer, such as a steel spacer or a stainless steel spacer, forexample. In some embodiments, spacer 1205 may have a substantiallyrectangular cross section. In some embodiments, spacer 1205 may behollow. Spacer 1205 includes a notch or recess, 1220, to accommodate abus bar, 1225. Notch or recess 1220 may form a channel that accommodatesthe length of bus bar 1225. Notch 1220 should be distinguished from achannel or a “mouse hole” in the spacer which may accommodate a bus barlead. An electrochromic device stack, 1202, is fabricated on glass lite815. Bus bar 1225 located on electrochromic device stack 1202 makeselectrical contact with one of the electrodes of electrochromic devicestack 1202.

Notch 1220 in spacer 1205 resides in the middle of the underside ofspacer 1205. The dimensions of notch 1220 are suitable to accommodatebus bar 1225, factoring in tolerances of the process used to form thenotch, as discussed above. In some embodiments, the notch width is about2 millimeters to about 5 millimeters, and the notch height is about 0.1millimeters to 1 millimeter. In some embodiments, the notch width isabout 3 millimeters to 4 millimeters, and the notch height is about 0.1millimeter to about 0.5 millimeters.

Comparing notch 1220 shown in FIG. 8 to notch 1101 shown in FIG. 7,notch 1220 is in the middle of the underside of the spacer and notch1101 is at the interior edge of the underside of the spacer. In otherregards, however, the embodiment shown in FIG. 8 may be similar to theembodiment shown in FIG. 7. For example, many of the dimensions andother design features described with respect to FIG. 7 may apply equallyto FIG. 8. Spacer 1205 may be relatively thicker (wider) in thedirection parallel to the glass sheet compared to conventional metalspacers. A conventional metal spacer is approximately 6 millimeters inwidth. Spacer 1205 is about two times to about two and one half times(about 2× to about 2.5×) that width. For example, spacer 1205 may beabout 10 millimeters to about 15 millimeters, about 13 millimeters toabout 17 millimeters, or about 11 millimeters wide. This additionalwidth may provide a greater margin of error in a sealing operationcompared to a conventional spacer. In some embodiments, the bus bar isabout 2 millimeters to about 3 millimeters in width and about 0.01millimeters to about 0.1 millimeter in height (thickness). The bus barlength depends on the window size. In some embodiments, a bus bar mayhave a length about the length of the electrochromic device. The basicIGU primary seal is comprised of interfaces between glass lites 1210 and1215 and primary seal material (e.g., PIB), 1230, and between primaryseal material 1230 and spacer 1205.

In some embodiments, the channel for the bus bar lead is located, butneed only penetrate part way under the spacer because the bus barresides midway underneath the spacer. In some embodiments, the bus barlead channel resides on an outside edge of the spacer or on an outsideedge of a corner of the spacer.

In some embodiments, the electrochromic device stack 1202 when in acolored state may color all the way under the spacer such thatelectrochromic device stack 1202 is substantially uniformly colored.Further, the bus bar may not be visible.

g. Combining Obscuring Techniques

In certain embodiments, a combination of the above-described obscuringtechniques may be employed in a single EC glass structure. In theillustrated example shown in FIG. 1A for example, bus bar 1 160(a) maybe an optically unobtrusive bus bar and an obscuring layer may be usedunder bus bar 2 160(b). In this example, both bus bars will not bevisible in the untinted state since bus bar 1 is transparent and bus bar2 is blocked from view by the obscuring layer. In the tinted state, busbar 2 will continue to be blocked from view.

Although the foregoing disclosed embodiments have been described in somedetail to facilitate understanding, the described embodiments are to beconsidered illustrative and not limiting. It will be apparent to one ofordinary skill in the art that certain changes and modifications can bepracticed within the scope of the appended claims.

One or more features from any embodiment may be combined with one ormore features of any other embodiment without departing from the scopeof the disclosure. Further, modifications, additions, or omissions maybe made to any embodiment without departing from the scope of thedisclosure. The components of any embodiment may be integrated orseparated according to particular needs without departing from the scopeof the disclosure.

What is claimed is:
 1. An insulated glass unit (IGU) comprising: firstand second substantially transparent substrates; a spacer between thefirst and second substantially transparent substrates; a primary sealbetween the spacer and the first substantially transparent substrate andbetween the spacer and the second substantially transparent substrate;an electrochromic device on at least one of the first and secondsubstantially transparent substrates; and a bus bar associated with theelectrochromic device and located in the primary seal, the bus barcamouflaged to blend in with its background.
 2. The IGU of claim 1,wherein camouflaged means having minimal optical contrast between thebus bar and the primary seal and/or spacer of the IGU.
 3. The IGU ofclaim 2, wherein the bus bar is made of an electrically conductivematerial comprising a tinting agent configured to approximate the colorof the bus bar to that of the primary seal and/or spacer of the IGU. 4.The IGU of claim 3, wherein the tinting agent comprises carbon black,graphite and/or graphene.
 5. An electrochromic glass structurecomprising: a substantially transparent substrate; an electrochromicdevice disposed on the substantially transparent substrate, theelectrochromic device having one or more transparent conductive layers;a bus bar configured to power the electrochromic device; and an opaqueobscuring layer located in a region between the bus bar and thesubstantially transparent substrate.
 6. The electrochromic glassstructure of claim 5, wherein the opaque obscuring layer has at least awidth configured to block view of the bus bar from an observer outsidethe electrochromic glass structure.
 7. The electrochromic glassstructure of claim 6, wherein the opaque obscuring layer has a widthgreater than the width of the bus bar.
 8. An IGU comprising: a firstpane having a first substantially transparent substrate, anelectrochromic device disposed on the first substantially transparentsubstrate, the electrochromic device comprising a first transparentconductive layer proximal the first substantially transparent substrate,an electrochromic stack, and a second transparent conductive layer; asecond pane having a second substantially transparent substrate; aspacer between the first and second panes; a primary sealant adheringthe spacer to the first and second panes; a pair of bus bars on thefirst transparent conductive layer, nearest the first pane; and one ormore transparent bus bars on the second transparent conductive layer. 9.The IGU of claim 8, wherein the pair of bus bars are located between thespacer and the first substantially transparent substrate such that thespacer blocks view of the pair of bus bars from an observer viewingthrough the second pane, and wherein the pair of bus bars are made ofmaterials configured to match the color to the spacer and/or the primarysealant of the IGU.
 10. The IGU of claim 8, wherein the one or moretransparent bus bars are in the viewable region of the IGU.
 11. The IGUof claim 10, further comprising an additional one or more transparentbus bars in electrical communication with the first transparentconductive layer and also in the viewable region of the IGU.
 12. The IGUof claim 11, wherein the additional one or more transparent bus bars arepatterned onto the first substantially transparent substrate and thenthe first transparent conductor layer is fabricated thereon.
 13. The IGUof claim 11, wherein the additional one or more transparent bus bars areembedded in the first substantially transparent substrate in at least inthe viewable region of the of the IGU.
 14. An IGU or laminatecomprising: a) an electrochromic device on at least one transparentsubstrate, of at least two transparent substrates of the IGU orlaminate; and b) at least one transparent bus bar configured toelectrically power the electrochromic device.
 15. The IGU or laminate ofclaim 14, wherein the transparent bus bar comprises a transparentconductive material embedded with conductive particles.
 16. The IGU orlaminate of claim 15, wherein the conductive particles arenanoparticles.
 17. The IGU or laminate of claim 16, wherein theconductive particles are metal particles or carbon-based particles. 18.The IGU or laminate of claim 17, wherein the conductive particles aresilver nanoparticles.
 19. The IGU or laminate of claim 17, wherein theconductive particles are graphene nanoparticles.
 20. The IGU or laminateof claim 14, wherein the at least one transparent bus bar is a thinlayer of metal or metal alloy.
 21. The IGU or laminate of claim 20,wherein the thin layer of metal or metal alloy is between about 1 nm andabout 10 nm thick.
 22. The IGU or laminate of claim 20, wherein the thinlayer of metal or metal alloy is less than about 5 nm thick.